Electric machines are utilized in motor vehicles as so-called starter-generators for starting the internal combustion engine in the motor mode of the electric machine, on the one hand and, on the other hand, for generating current for the vehicle electrical system and for charging the motor vehicle battery in the generator mode of the electric machine. Such electric machines can be connected to the internal combustion engine or to the crankshaft via a belt, for example via the V-ribbed belt of the internal combustion engine (so-called belt-driven starter-generators).
DE 10 2009 055 062 A1, for example, describes a method for validating a drive torque applied by an electric machine in a hybrid drive of a motor vehicle. In this case, a check is carried out to determine whether the drive torque applied by the electric machine is accurately determined. The method is based on a check carried out to determine whether the torque of the electric motor corresponds to the drag torque of the internal combustion engine.